Replying to Zipfit new customer

Recently wanted to make an upgrade to my boot setup, which is currently a 2023 k2 method. I have skied Intuition Pro liners and preferred the feel over the cheaper method liner, but I had to pick this boot up quickly for a trip. The issue I've been having is that my current boots are slightly too loose, especially when wearing thinner socks. A size down is what I had previously, same shell and everything, and even with excessive punching and molding, it was unbearable to ski. These new methods, being the same shell and all, now feel ever so slightly too large, and lack heel lock. I did a solid amount of research on Zipfit freeride liners, and hopefully, this will be a good solution. Is this the right purchase to be made? Or am I better off opting for a completely different shell via bootfitter? My justification for the purchase of new liners is that I might as well use the shell I have now...